From: Xin Chen (xinchen_at_ic.sunysb.edu)
Date: Tue Apr 06 2004 - 00:05:19 CDT
Hi, all
I used Langevin dynamics to control the temperature in the simulation. But
it seems that I cannot restart my simulation with it. First time, I did
simulation to 1.6M timestep, and then I restart it from 1.5M timestep. The
energy results from 1.5M to 1.6M timestep for these two simulation are
different. The force field I used is AMBER. I wonder if anyone know why and
how to solve this problem. Thanks. The configuration files is as follows
First one
===================================================
numsteps 1600000
# initial config
temperature 373.16
seed 12345
#rigidBonds all
# output params
#cwd ./out0
outputname botulinum_water
binaryoutput no
outputEnergies 500
outputMomenta 0
outputTiming 500
outputPressure 0
# integrator params
timestep 1.0
# force field parameters
exclude scaled1-4
1-4scaling 1.0
switching on
switchdist 10.0
cutoff 12.0
pairlistdist 14.0
pairlistsPerCycle 10
margin 4.0
stepspercycle 20
langevin on # langevin dynamics
langevinFile 3bta_wat.pdb
langevinDamping 5.0 # damping coefficient of 5/ps
langevinTemp 373.16 # random noise at this level
maximumMove 0.5
wrapWater on # wrap water to central cell
wrapAll on # wrap other molecules too
wrapNearest off # use for non-rectangular cells
# we are using amber force field
amber yes
parmfile 3bta_wat.top
ambercoor 3bta_wat.crd
readexclusions no
scnb 1.0
binaryrestart yes
DCDfile bta_wat.dcd
DCDfreq 10000
DCDUnitCell yes
velDCDfile bta_wat.vcd
velDCDfreq 20000
restartname bta_wat
restartfreq 5000
restartsave yes
===================================================
Second one:
Same, add one line:
firsttimestep 1500000
===================================================
Sincerely yours,
Xin Chen
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